MOS Capacitance-Voltage Characteristics Ⅱ.Sensitivity of Electronic Trapping at Dopant Impurity from Parameter Variations

Low-frequency and high-frequency Capacitance-Voltage（C-V） curves of Metal-Oxide-Semiconductor Capacitors（MOSC）,including electron and hole trapping at the dopant donor and acceptor impurities,are presented to illustrate giant trapping capacitances,from>0.01C_ox to>10C_ox.Five device and materials parameters are varied for fundamental trapping parameter characterization,and electrical and optical signal processing applications.Parameters include spatially constant concentration of the dopant-donor-impurity electron trap,N_DD,the ground state electron trapping energy level depth measured from the conduction band edge, E_C—E_D,the degeneracy of the trapped electron at the ground state,g_D,the device temperature,T,and the gate oxide thickness,x_OX.     

化学氧化法聚吡咯导电性能与导电机理

采用化学氧化法制备了导电聚吡咯(PPy).运用SEM和TEM表征了PPy的形貌,利用四探针技术测试了材料的电导率,对影响其电导率的因素进行了讨论,并对其导电机理进行研究.结果表明,氧化剂用量、反应温度、反应时间、掺杂剂的种类等对最终所得材料的导电性能及结构形态有较大的影响.以苯磺酸钠作掺杂剂,FeCl3/Py摩尔比为1.0,冰浴条件下,反应0.5h所得材料电导率最高,为58.82S/cm,其中以2-萘磺酸为掺杂剂所得PPy微观形貌呈现罕见的纤维状.电导率相对较高的PPy,说明其本身掺杂状况使它在氧化掺杂时随导带和价带间的能级差减小,禁带变窄,载流子移动阻力小;阴离子的掺杂和脱掺杂变得容易,因而电导率高.     

Si-Ti-B掺杂金刚石/硬质合金复合体的性能

金刚石粒度和掺杂量两因素对Si-Ti-B掺杂金刚石/硬质合金复合体的金刚石层的抗弯强度和耐磨性的综合影响,可以归结为平均自由程与机械性能的关系。在强度(或耐磨性)与平均自由程的关系曲线中,存在最大值。对于低掺杂量材料,强度随平均自由程(粘结相层厚度)的减少而降低。对于高掺杂量材料,强度随粘结相层厚度的增大而下降。Si-Ti-B掺杂烧结金刚石的耐热性高于钴粘结金刚石。     

Numerical Simulation of Dopant Diffusion for Laser-Doped Crystalline Silicon

In this paper, the nonlinear numerical simulation of pulsed laser melting of crystalline silicon and phosphorus dopant liquid-phase diffusion has been established by the finite element method implemented in ANSYS. The melt front behavior as a function of time is described. The experimental SIMS work is intended to be used to validate the numerical model. The numerical simulation result is in good agreement with the corresponding experimental data.     

掺杂离子在LHPG单晶光纤中的分布

用电子能量色散谱（ＥＤＳ）分析了Ｎｄ＾３＾＋，Ｅｒ＾３＾＋和Ｃｒ＾３＾＋等掺杂离子在ＹＡＧ单晶光纤中的分布，实验发现：掺杂离子的分凝系数不同，其分布规律也不同，根据晶体的溶液生长理论，导出了掺杂离子分布方程，它与实验结果相符较好。     

Concentrations of native and gold defects in HgCdTe from first principles calculations

We have studied the defect formation energies of the various native (vacancies, interstitials, and antisites) and Au defects in Hg_1−xCd_xTe using density functional-based total energy calculations with ultrasoft pseudo-potentials. These studies are important for infrared (IR) detection technology where the device performance can be severely degraded because of defects. To calculate formation energies, we modeled the neutral and charged defects using supercells containing 64 atoms. From the formation energies, we have determined the defect concentrations as a function of stoichiometry and temperature. We find the prevalent neutral defects to be Au at the Hg site (Au_Hg ), Hg vacancies (V_Hg ), and Te antisites (Te_Hg ). We have also explicitly studied charged defects and have found Te _Hg ²⁺ , Au _Hg ¹⁻ , V _Hg ¹⁻ , V _Hg ²⁻ , and V _Te ²⁺ to have low formation energies. We have identified Au_Hg to be the prevalent Au defect, having concentrations several orders of magnitude greater than the other Au defects. We find that the charge state of V_Hg is primarily (1−) or (2−) depending on the electronic chemical potential.     

Effects of dopant,temperature, and strain rate on the mechanical properties of micrometer gold-bonding wire

An experimental study on the thermomechanical properties of microelectronic gold-bonding wires was conducted using high-precision, microforce tensile tests. The load-displacement behavior of three types of gold wire (GL-2 type, FA type, and SR type) was carefully recorded for determining the elastic modulus and stress-strain curves. Tests were conducted with miniature specimens at temperatures ranging from room temperature to 250°C and load rates on the order of 1 mm/min and 10 mm/min. The testing results indicated that the tensile strength of all three types of wire decreased with temperature, especially the SR type. The load strain rate has a significant effect on the SR type but little effect on the GL-2 and FA wires. The stress-strain curves from these tests were analyzed to fit into empirical constitutive models that account for the strain, temperature, and strain-rate effects.     

Depletion layer in pn-junction of diamond with phosphorus donor and boron acceptor

In order to understand characteristics of diamond pn-junction, ionized dopant and carrier profiles in pn-junction of diamond with phosphorus (P) donor and boron (B) acceptor are calculated. There exists a large transition region at a depletion layer edge due to Debye tailing at room temperature (RT). The length of Debye tailing, λ, is reduced with increasing compensation ratios and temperatures. The Debye tailing is predicted to facilitate an early effect of a pnp-bipolar transistor.     

Observation of indium-vacancy and indium-hydrogen interactions in Hg1−xCdxTe

We have used a nuclear hyperfine technique, perturbed γγ angular correlation (PAC), to study the interactions between¹¹¹In and native defects and impurities in Hg_1−xCd_xTe. The PAC technique uses the quadrupole interaction of¹¹¹In with local electric field gradients to characterize the local environment of this donor dopant. We observed that when In was diffused into a bulk or thin film sample of Hg_1−xCd_xTe (x=0.21 and x=0.3) at 350°C and the sample was slow cooled, the In occupied sites with near-cubic symmetry, presumably the substitutional metal site. However, when the sample was quenched, a fraction of the In was incorporated into defects characterized by quadrupole interaction strengthsv _Q1 andv _Q2 and asymmetries of ν₁=ν₂=0.08. These defects are attributed to the trapping of a metal vacancy at a next-nearest neighbor site to the In atom. The introduction of hydrogen by boiling the samples in distilled water for >4h eliminated the previously observed PAC signals and created defects characterized byv _Q3=35 MHz, ν₃ <0.1 andv _Q4=MHz, ν₄ <0.1. These defects are attributed to the decoration of the In-V_Hg complex by a hydrogen atom. Hall effect measurements showed that hydrogenation increased the hole concentration in p-type quenched samples and even converted n-type indium-doped samples to p-type. A possible model for hydrogen incorporation which includes self-compensation by vacancy creation is suggested.